Hidden features of NAD-RNA epitranscriptome in Drosophila life cycle.

Nicotinamide adenine dinucleotide (NAD), a nucleotide-containing metabolite, can be incorporated into the RNA 5'-terminus to result in NAD-capped RNA (NAD-RNA). Since NAD has been heightened as one of the most essential metabolites in cells, its linkage to RNA represents a critical but poorly studied modification at the epitranscriptomic level. Here, we design a highly sensitive method, DO-seq, to capture NAD-RNAs. Using Drosophila, we identify thousands of previously unexplored NAD-RNAs and their dynamics in the fly life cycle, from embryo to adult. We show the evidence that chromosomal clustering might be the structural basis by which co-expression can couple with NAD capping on physically and functionally linked genes. Furthermore, we note that NAD capping of cuticle genes inversely correlates with their gene expression. Combined, we propose NAD-RNA epitranscriptome as a hidden layer of regulation that underlies biological processes. DO-seq empowers the identification of NAD-capped RNAs, facilitating functional investigation into this modification.

Efficacy and safety of glucocorticoids use in patients with COVID-19: a systematic review and network meta­analysis.

BACKGROUND: Currently, some meta-analyses on COVID-19 have suggested that glucocorticoids use can reduce the mortality rate of COVID-19 patients, utilization rate of invasive ventilation, and improve the prognosis of patients. However, optimal regimen and dosages of glucocorticoid remain unclear. Therefore, the purpose of this network meta-analysis is to analyze the efficacy and safety of glucocorticoids in treating COVID-19 at regimens. METHODS: This meta-analysis retrieved randomized controlled trials from the earliest records to December 30, 2022, published in PubMed, Embase, Cochrane Library, CNKI Database and Wanfang Database, which compared glucocorticoids with placebos for their efficacy and safety in the treatment of COVID-19, Effects of different treatment regimens, types and dosages (high-dose methylprednisolone, very high-dose methylprednisolone, Pulse therapy methylprednisolone, medium-dose hydrocortisone, high-dose hydrocortisone, high-dose dexamethasone, very high-dose dexamethasone and placebo) on 28-day all-caused hospitalization mortality, hospitalization duration, mechanical ventilation requirement, ICU admission and safety outcome were compared. RESULTS: In this network meta-analysis, a total of 10,544 patients from 19 randomized controlled trials were finally included, involving a total of 9 glucocorticoid treatment regimens of different types and dosages. According to the analysis results, the 28-day all-cause mortality rate was the lowest in the treatment with pulse therapy methylprednisolone (OR 0.08, 95% CI 0.02, 0.42), but the use of high-dose methylprednisolone (OR 0.85, 95% CI 0.59, 1.22), very high-dose dexamethasone (OR 0.95, 95% CI 0.67, 1.35), high-dose hydrocortisone (OR 0.64, 95% CI 0.34, 1.22), medium-dose hydrocortisone (OR 0.80, 95% CI 0.49, 1.31) showed no benefit in prolonging the 28-day survival of patient. Compared with placebo, the treatment with very high-dose methylprednisolone (MD = -3.09;95%CI: -4.10, -2.08) had the shortest length of hospital stay, while high-dose dexamethasone (MD = -1.55;95%CI: -3.13,0.03) and very high-dose dexamethasone (MD = -1.06;95%CI: -2.78,0.67) did not benefit patients in terms of length of stay. CONCLUSIONS: Considering the available evidence, this network meta­analysis suggests that the prognostic impact of glucocorticoids in patients with COVID-19 may depend on the regimens of glucocorticoids. It is suggested that pulse therapy methylprednisolone is associated with lower 28-day all-cause mortality, very high-dose methylprednisolone had the shortest length of hospital stay in patients with COVID-19. TRIAL REGISTRATION: PROSPERO CRD42022350407 (22/08/2022).

Effect of Raw Material Particle Size on the Synthesis of La2Zr2O7 by the Molten Salt Method.

In this study, a process based on the molten salt method was proposed to prepare La2Zr2O7 for improving the kinetic conditions of synthesis. Considering that the particle size of raw materials is an important factor that may have an effect on the kinetic process of synthesis, ZrO2 and La2O3 with different particle sizes are used as raw materials, and the synthesis experiment is carried out at 900-1300 °C through the combination of raw materials with different particle sizes. The results show that the particle size of ZrO2 plays an important role in the synthesis of La2Zr2O7. The "dissolution precipitation" mechanism of the synthesis process in the NaCl-KCl molten salt was confirmed by SEM image observation. Furthermore, the influence of the dissolution rate of each raw material on the synthesis reaction was studied by introducing the Noyes-Whitney equation and testing the specific surface area and solubility of each raw material, and it was confirmed that the particle size of ZrO2 was the limiting condition of the synthesis reaction, and use of ZrO2(Z50) with a nominal particle size of 50 nm could significantly improve the kinetic condition of the reaction, thus reducing the synthesis temperature, which can help realize the energy-saving and -efficient synthesis of pyrochlore La2Zr2O7.

Inhibition of sphingosine-1-phosphate receptor 3 suppresses ATP-induced NLRP3 inflammasome activation in macrophages via TWIK2-mediated potassium efflux.

Background: Inhibition of sphingosine kinase 1 (SphK1), which catalyzes bioactive lipid sphingosine-1-phosphate (S1P), attenuates NLRP3 inflammasome activation. S1P exerts most of its function by binding to S1P receptors (S1PR1-5). The roles of S1P receptors in NLRP3 inflammasome activation remain unclear. Materials and methods: The mRNA expressions of S1PRs in bone marrow-derived macrophages (BMDMs) were measured by real-time quantitative polymerase chain reaction (qPCR) assays. BMDMs were primed with LPS and stimulated with NLRP3 activators, including ATP, nigericin, and imiquimod. Interleukin-1ß (IL-1ß) in the cell culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA). Intracellular potassium was labeled with a potassium indicator and was measured by confocal microscopy. Protein expression in whole-cell or plasma membrane fraction was measured by Western blot. Cecal ligation and puncture (CLP) was induced in C57BL/6J mice. Mortality, lung wet/dry ratio, NLRP3 activation, and bacterial loads were measured. Results: Macrophages expressed all five S1PRs in the resting state. The mRNA expression of S1PR3 was upregulated after lipopolysaccharide (LPS) stimulation. Inhibition of S1PR3 suppressed NLRP3 and pro-IL-1ß in macrophages primed with LPS. Inhibition of S1PR3 attenuated ATP-induced NLRP3 inflammasome activation, enhanced nigericin-induced NLRP3 activation, and did not affect imiquimod-induced NLRP3 inflammasome activation. In addition, inhibition of S1PR3 suppressed ATP-induced intracellular potassium efflux. Inhibition of S1PR3 did not affect the mRNA or protein expression of TWIK2 in LPS-primed BMDMs. ATP stimulation induced TWIK2 expression in the plasma membrane of LPS-primed BMDMs, and inhibition of S1PR3 impeded the membrane expression of TWIK2 induced by ATP. Compared with CLP mice treated with vehicle, CLP mice treated with the S1PR3 antagonist, TY52156, had aggravated pulmonary edema, increased bacterial loads in the lung, liver, spleen, and blood, and a higher seven-day mortality rate. Conclusions: Inhibition of S1PR3 suppresses the expression of NLRP3 and pro-IL-1ß during LPS priming, and attenuates ATP-induced NLRP3 inflammasome activation by impeding membrane trafficking of TWIK2 and potassium efflux. Although inhibition of S1PR3 decreases IL-1ß maturation in the lungs, it leads to higher bacterial loads and mortality in CLP mice.

Severe COVID-19 has a distinct phenotype from bacterial sepsis: a retrospective cohort study in deceased patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has caused more than 2 million deaths worldwide. Viral sepsis has been proposed as a description for severe COVID-19, and numerous therapies have been on trials based upon this hypothesis. However, whether the clinical characteristics of severe COVID-19 are similar to those of bacterial sepsis has not been elucidated. METHODS: We retrospectively compared the clinical data of non-surviving COVID-19 patients who were admitted to a 30-bed intensive care unit (ICU) in Wuhan Infectious Diseases Hospital (Wuhan, China) from 22 January 2020, to 28 February 2020, with those of non-surviving patients with bacterial sepsis who were admitted to the ICU in Zhongshan Hospital, Fudan University (Shanghai, China) from 3 July 2018, to 30 June 2020. RESULTS: A total of 53 COVID-19 patients and 26 septic patients were included in the analysis. The mean ages were 65.6 [standard deviation (SD): 11.1] and 70.4 (SD: 14.3) years in the COVID-19 cohort and sepsis cohort, respectively. The proportion of participants with hypertension was higher in non-survivors with COVID-19 than in non-survivors with sepsis (41.5% vs. 15.4%, P=0.020). The Sequential Organ Failure Assessment (SOFA) score of non-survivors with COVID-19 was lower than that of non-survivors with sepsis at ICU admission {4.0 [interquartile range (IQR): 3.0-6.0] vs. 7.5 [IQR: 5.8-11.0], P<0.001}. The clinical parameters at ICU admission assessed with principal component analysis and hierarchical cluster analysis showed that COVID-19 patients were distinct from bacterial septic patients. Compared with non-survivors with sepsis, non-survivors with COVID-19 had a higher neutrophil/lymphocyte ratio, total protein, globulin, lactate dehydrogenase (LDH), and D-dimer; a lower eosinophil count, procalcitonin, interleukin-6 (IL-6), total bilirubin, direct bilirubin, myohemoglobin, albumin/globulin ratio, activated partial thromboplastin time (APTT), prothrombin time (PT), and international normalization ratio (INR) at ICU admission. In addition, the levels of total protein, globulin, LDH, D-dimer, and IL-6 were significantly different between the two groups during the ICU stay. CONCLUSIONS: Patients with critical COVID-19 have a phenotype distinct from that of patients with bacterial sepsis. Therefore, caution should be used when applying the previous experience of bacterial sepsis to patients with severe COVID-19.

Inhibition of Sphingosine Kinase 1 Attenuates Sepsis-induced Microvascular Leakage via Inhibiting Macrophage NLRP3 Inflammasome Activation in Mice.

BACKGROUND: Sepsis is the overwhelming inflammatory response to infection, in which nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome plays a crucial role. Shingosine-1-phosphate is reported to evoke NLRP3 inflammasome activation. Sphingosine kinase 1 (SphK1) is the major kinase that catalyzes bioactive lipid shingosine-1-phosphate formation and its role in sepsis remains uncertain. The authors hypothesize that SphK1 elicits NLRP3 inflammasome activation and exacerbates sepsis. METHODS: Peripheral blood mononuclear cells were isolated from septic patients and healthy volunteers to measure messenger RNA (mRNA) expression. In mice, sepsis was induced by cecal ligation and puncture. Bone marrow-derived macrophages were prepared from C57BL/6J wild-type, Casp1, Nlrp3 and SphK1 mice. PF-543 was used as the specific inhibitor of SphK1. Mortality, peripheral perfusion, lung Evan's blue dye index, lung wet/dry ratio, lung injury score, lung myeloperoxidase activity, NLRP3 activation, and function of endothelial adherens junction were measured. RESULTS: SphK1 mRNA expression was higher in cells from septic patients versus healthy volunteers (septic patients vs. healthy volunteers: 50.9 ± 57.0 fold change vs. 1.2 ± 0.1 fold change, P < 0.0001) and was positively correlated with IL-1ß mRNA expression in these cells (r = 0.537, P = 0.012) and negatively correlated with PaO2/FIO2 ratios (r = 0.516, P = 0.017). In mice that had undergone cecal ligation and puncture, the 5-day mortality was 30% in PF-543-treated group and 80% in control group (n = 10 per group, P = 0.028). Compared with controls, PF-543-treated mice demonstrated improved peripheral perfusion and alleviated extravascular Evan's blue dye effusion (control vs. PF-543: 25.5 ± 3.2 ng/g vs. 18.2 ± 1.4 ng/g, P < 0.001), lower lung wet/dry ratio (control vs. PF-543: 8.0 ± 0.2 vs. 7.1 ± 0.4, P < 0.0001), descending lung injury score, and weaker lung myeloperoxidase activity. Inhibition of SphK1 suppressed caspase-1 maturation and interleukin-1ß release through repressing NLRP3 inflammasome activation, and subsequently stabilized vascular endothelial cadherin through suppressing interleukin-1ß-evoked Src-mediated phosphorylation of vascular endothelial cadherin. CONCLUSIONS: SphK1 plays a crucial role in NLRP3 inflammasome activation and contributes to lung injury and mortality in mice polymicrobial sepsis.

Prognostic roles of the expression of sphingosine-1-phosphate metabolism enzymes in non-small cell lung cancer.

BACKGROUND: Sphingosine-1-phosphate (S1P), a bioactive lipid, is generally increased in human non-small cell lung cancer (NSCLC). Evidence has shown that the levels of enzymes in S1P metabolism were associated with clinical outcomes in patients with NSCLC. Nevertheless, the roles of mRNA expression of major enzymes (SPHK1, SPHK2 and SGPL1) in S1P metabolism for predicting outcomes in NSCLC patients have not been determined. METHODS: "The Kaplan-Meier plotter" (the KM plotter) is an online database which contains gene expression and clinical data of 1,928 NSCLC patients. In this study, we analyzed the relationship between mRNA expression of major enzymes in S1P metabolism and overall survival (OS) in 1,926 NSCLC patients with the KM plotter. Further analyses stratified by smoking history, non-metastasis patents, clinical stages, negative surgical margin, chemotherapy and radiotherapy were also performed. RESULTS: High SPHK1 mRNA expression [hazard ratio (HR) 1.47, 95% confident interval (CI): 1.28-1.68, P=2.6e-08] was significantly correlated to worse OS, but high SPHK2 (0.66, 95% CI: 0.59-0.75, P=1.9e-10) or SGPL1 (HR 0.64, 95% CI: 0.55-0.75, P=8.7e-09) mRNA expression was in favor of better OS in NSCLC patients. CONCLUSIONS: The mRNA expression of SPHK1, SPHK2, and SGPL1 is potential predictor of outcomes in NSCLC patients.

M2 macrophages promote pulmonary endothelial cells regeneration in sepsis-induced acute lung injury.

BACKGROUND: Macrophages can polarize to M2 phenotype to decrease inflammation and encourage tissue repair. Nonetheless, its role in sepsis-induced acute lung injury and its effect on endothelial cells (ECs) regeneration remains unknown. The aim of the current study was to explore the impact of M2 macrophages on pulmonary ECs proliferation in sepsis-induced acute lung injury. METHODS: We co-cultured mouse lung microvascular endothelial cells (MLMVECs) with M2 macrophages following LPS challenge. M2 macrophages were intratracheally transplanted into mice subjected to cecal ligation and puncture (CLP). We further performed cytokine array for the supernatant from M2 macrophages and serum from mice subjected with CLP. RESULTS: We found both co-culture with M2 macrophages and treating with supernatant from M2 macrophages increased ECs viability following LPS challenge. Intratracheal transplantation of M2 macrophages markedly promoted pulmonary ECs proliferation, manifesting as attenuation of lung microvascular permeability and lung tissue edema, as well as improvement of survival rate. We further found that CXCL12, IL-1ra, TIMP-1, IL-4, and CXCL1 were increased in the supernatant of M2 macrophages in vitro. G-CSF and Complement Component 5a (C5/C5a) were increased in the serum of the M2-transplanted mice. CONCLUSIONS: The present study suggested M2 macrophages could promote ECs proliferation in sepsis-induced ALI through secretion of anti-inflammatory cytokines and growth factors.

The preventive effect of antiplatelet therapy in acute respiratory distress syndrome: a meta-analysis.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a life-threatening condition with high mortality that imposes a serious medical burden. Antiplatelet therapy is a potential strategy for preventing ARDS in patients with a high risk of developing this condition. A meta-analysis was performed to investigate whether antiplatelet therapy could reduce the incidence of newly developed ARDS and its associated mortality in high-risk patients. METHODS: The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Medline, and the Web of Science were searched for published studies from inception to 26 October 2017. We included randomized clinical trials, cohort studies and case-control studies investigating antiplatelet therapy in adult patients presenting to the hospital or ICU with a high risk for ARDS. Baseline patient characteristics, interventions, controls and outcomes were extracted. Our primary outcome was the incidence of newly developed ARDS in high-risk patients. Secondary outcomes were hospital and ICU mortality. A random-effects or fixed-effects model was used for quantitative synthesis. RESULTS: We identified nine eligible studies including 7660 high-risk patients who received antiplatelet therapy. Based on seven observational studies, antiplatelet therapy was associated with a decreased incidence of ARDS (odds ratio (OR) 0.68, 95% confidence interval (CI) 0.52-0.88; I2 = 68.4%, p = 0.004). In two randomized studies, no significant difference was found in newly developed ARDS between the antiplatelet groups and placebo groups (OR 1.32, 95% CI 0.72-2.42; I 2 = 0.0%, p = 0.329). Antiplatelet therapy did not reduce hospital mortality in randomized studies (OR 1.15, 95% CI 0.58-2.27; I 2 = 0.0%; p = 0.440) or observational studies (OR 0.80, 95% CI 0.62-1.03; I2 = 31.9%, p = 0.221). CONCLUSIONS: Antiplatelet therapy did not significantly decrease hospital mortality in high-risk patients. However, whether antiplatelet therapy is associated with a decreased incidence of ARDS in patients at a high risk of developing the condition remains unclear.